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Mesh > Reduce

Reduces the number of polygons in a selected region of a polygon mesh, optionally taking into account UVs and vertex colors as it chooses which areas to reduce.

Reduce is useful when you need to lower the number of polygons in a particular region of a polygon mesh. The polygon reduction is controlled via a polyReduce node that gets created. This lets you experiment with the amount of blend reduction and can be removed altogether should you wish to return the polygon mesh to its original pre-reduced state.

You can also preserve the original vertex positions to minimize the overall shape change that occurs on the mesh as a result of the reduction.

You can optionally paint the amount of polygon reduction using the Mesh > Paint Reduce Weights Tool.

Related topics

Mesh > Reduce >

Reduce number of faces

Reduce by (%): Maya attempts to reduce the number of polygons in the selected mesh or meshes by the specified percentage. The actual reduction may not match this number exactly.
Keep quads: Maya attempts to maintain any existing quad topology on the mesh as it reduces. The slider range is between 0 and 1. The default setting is 1 (maximum effect). Reduce the slider value or increase the Triangle compactness option if the reduction results in an undesirable shape change.
Triangle compactness: Controls the degree to which Maya sacrifices mesh shape accuracy to produce better triangles, as a value from 0 to 1.

A value of 0 specifies to reproduce the original mesh shape as accurately as possible while reducing, no matter what kind of triangles are produced. A value of 1 specifies to sacrifice accuracy as much as possible to produce regular equilateral triangles.

Values closer to 0 can produce long skinny triangles that can be hard to work with. Values closer to 1 can produce reduced meshes that do not match the shape of the original.
Triangulate before reducing: Converts the polygons to triangles before reducing them.

By default this option is off in order to maintain the quad topology on a mesh. If three or four sided polygon topology is not an issue, turn this option on.
Keep original (for paint weights): The original mesh is preserved for the purposes of using the paint weights features. See Mesh > Paint Reduce Weights Tool.
Cache reduction (for speed): Saves intermediate versions of the reductions in memory and is useful when multiple reduction iterations are anticipated. If memory reduction is an issue, turn this option off.

Reduction Influencers

These options take extra information (beside shape) into account when reducing the mesh.

UVs: Reduces polygons to preserve UV mapping as much as possible. Turning this option on will preserve texture placement between the original and reduced polygons.
Color per vertex: Reduces polygons so that color per vertex data (such as prelighting/baking and painting) is preserved as much as possible. Turning this option on will devote more polygons in the reduced mesh to areas with color changes, and fewer polygons to areas with flat color to preserve the look of the original.

Preserve

Mesh borders: Maya attempts to preserve the shape of polygon borders (edges that are not shared by other polygons).
UV borders: Maya attempts to preserve the shape of UV borders as it reduces.

Turning this on can give unpredictable results if you have a lot of UV borders. Try sewing as many UV pieces together as possible before reducing.

NoteIf a polygonal surface has numerous UV seams on it and if the Mesh > Reduce operation is performed with UV Borders turned on, there is a good chance the object will not reduce at all, since the reduction algorithm is attempting to maintain the UV borders (seams) that are on the object.
If you don’t mind losing your UV seams, turn off UV Borders to successfully reduce your polygonal surface.
Hard edges: Maya attempts to preserve the shape of edges marked “hard” as it reduces.

You can set edges on a mesh to be hard or soft using Normals > Soften Edge or Normals > Harden Edge. Marking edges as “hard” can result in more shape retention than painting reduction weights.
Vertex positions: Locks the position of vertices thereby preserving the original shape of the mesh as much as possible.